European patent No. EP 0 71 5 396 discloses a motorized fan for a motor vehicle, incorporating its own electronic control means and comprising a closed cylindrical casing, an armature contained within the casing, a housing arranged as an axial extension of the armature, and an electronic device for controlling the motor, contained within this housing. The location of the electronic control means is close to the motor, which enables long connecting wires to be dispensed with, and therefore reduces the effects of electromagnetic disturbance. The location of the control housing as an axial extension of the motor casing enables the whole of the radial peripheral space around the motor to be left free. This space contains the blades of the fan driven by the motor, and the stream of air impelled by the fan passes axially through this free space, and therefore flows over the motor casing. The control housing is separated from the motor casing by a layer of air. The electronic logic and power components arranged within the housing, some of which are vulnerable to high temperatures, are therefore largely insulated from the heat given off by the motor. The above mentioned layer of air is favorable to the evacuation of the heat given off by the motor and by the electronic components.
However, this structure comprising a casing and a housing, separated from each other in the axial direction by a layer of air, does require a large amount of space to be provided in the axial direction. In this connection, at the present time there is an increasing demand for axially compact motorized fans for motor vehicles.